Tar Paper Under Laminate Flooring: What to Use and What to Avoid

Laminate flooring requires a stable, moisture-aware base and a suitable underlayment to ensure quiet walking, proper install, and long-term durability. Tar paper, commonly known as asphalt-saturated felt, is sometimes discussed as a quick moisture barrier option. This article explains whether tar paper is appropriate beneath laminate, what risks it presents, and what alternatives deliver better performance for typical American homes.

Tar Paper And Laminate: What It Is

Tar paper is a simple, inexpensive roll generally used as a moisture barrier in roofing and some flooring projects. It is made from asphalt-saturated felt or a similar material. In theory, it can slow moisture transfer from the subfloor to the laminate. In practice, tar paper falls short of the needs of modern laminate installations because it does not provide a uniform, continuous vapor barrier or a stable, impact-absorbing layer. Laminate requires a smooth, level surface with an underlayment that cushions, reduces sound, and helps with moisture management.

Why Tar Paper Is Not Ideal For Laminate

Using tar paper directly under laminate can lead to several issues. First, tar paper is not designed to meet current building codes for interior moisture control in many regions. It can deteriorate over time, especially in spaces with humidity fluctuations, creating gaps or crinkles that telegraph through the laminate surface. Second, tar paper lacks a consistent vapor barrier compared to purpose-made underlayments that combine a vapor barrier with sound reduction. Third, tar paper does not provide the rigid or semi-rigid support needed to prevent telegraphing of subfloor imperfections, which can cause creaks and pinch points in planks. Finally, it often does not meet the installation instructions of many laminate brands, potentially voiding warranties.

Proper Underlayments For Laminate Flooring

Choosing the right underlayment is essential for performance and warranty protection. In most homes, the best options fall into two categories: foam or cork underlayments with a built-in or separate moisture barrier, and specialized vapor barriers for concrete slabs. The key benefits of approved underlayments include moisture control, sound insulation, and a smooth, consistent base for click-Laminate installations.

• Foam underlayment with a moisture barrier: A commonly recommended option for many floating laminate installs. Provides cushioning, reduces sound, and blocks minor moisture from beneath if a vapor barrier is included.
• Cork underlayment: Offers excellent sound absorption and a natural feel underfoot; often paired with a polyethylene vapor barrier for moisture control.
• Composite underlayment with integrated vapor barrier: Combines cushion and a moisture barrier in one sheet, ensuring a uniform layer and simplifying installation.
• Concrete slab specifics: Use a high-quality polyethylene or foil-faced vapor barrier designed for interior moisture, plus a thin cushion to accommodate temperature expansion and contraction.

Installation Tips And Considerations

To optimize laminate performance, follow these guidelines. First, ensure the subfloor is clean, dry, and level according to manufacturer tolerances. Any slope, high spots, or damaged patches should be addressed before laying underlayment. Second, select an underlayment that matches the subfloor type (wood subfloor, concrete slab, or existing boards). Third, avoid tar paper entirely in favor of purpose-built underlayments that carry the manufacturer’s warranty. Fourth, maintain adequate expansion gaps around walls and fixed objects as specified by the laminate brand. Finally, if moisture is a concern (basements, below-grade spaces, or areas with potential groundwater intrusion), consider a vapor-retarder rated for the expected humidity range and install according to the product’s instructions.

For spaces with potential moisture sources, such as kitchens or bathrooms, Laminate manufacturers often require a moisture barrier or barrier-enabled underlayment. Check the product details for maximum room-relative humidity and moisture tolerance. Remember that tar paper does not seal against high humidity or flooding risk effectively, so it should not be relied upon as a primary moisture solution.

Common Misconceptions

Some homeowners assume tar paper is an easy, cost-saving alternative to underlayment. In practice, tar paper’s limitations—poor durability, inconsistent barrier properties, and lack of compatibility with many laminate warranties—undermine long-term performance. Others might consider tar paper as a temporary solution during a quick remodel; however, most laminate brands advise against it. For best results, choose an underlayment specifically designed for laminate flooring and follow the manufacturer’s installation guidelines to preserve warranty coverage and floor performance.

Practical Takeaways

When installing laminate flooring in a typical American home, avoid tar paper underlayment. Instead, select an approved underlayment that provides moisture control, sound dampening, and surface stability. If moisture is a concern, use a dedicated vapor barrier under a compatible underlayment, or choose a laminate product with a built-in moisture protection system. Always verify compatibility with the flooring brand, climate considerations, and local building codes. With the right underlayment, laminate floors will install smoothly, feel comfortable underfoot, and maintain their appearance for years to come.